1. Field of the Invention
The present invention relates to an ink jet device with a purge mechanism for recovering from misfires or otherwise defective ejections.
2. Description of the Related Art
Misfires or otherwise defective ejections sometimes occur in jet devices for ejecting ink droplets from nozzles to print dot patterns. The misfires or defective ejections can be caused by a variety of reasons, such as dust or dirt clinging to the nozzles, air entering the nozzles, or ink drying in the nozzles.
Japanese Patent Application Kokai No. SHO-62-263058 discloses an example of a mechanism for restoring an ink jet printer to a proper ejection condition. The carriage of the printer is moved to bring a print head mounted on the carriage into alignment with a cap of a purge system. When the carriage is in this predetermined position, a switching mechanism, which includes a plurality of rachet gears, operates to switch drive force of a sheet feed motor to drive a negative pressure means of the purge system. The negative pressure means then generates a negative pressure in the cap, thereby sucking ink and foreign matter from the nozzles and nozzle face of the head.
However, because the drive force is switched by a plurality of ratchet gears, the mechanism is complicated and requires a large number of parts. This obstructs attempts to down-size the printer.